Problem: Vanessa ate 3 slices of cake. Umaima ate 1 slice. If Vanessa ate $\dfrac{3}{5}$ of the cake, what fraction of the cake was eaten?
Solution: If 3 slices represent $\dfrac{3}{5}$ of the cake, there must have been a total of 5 slices. $\text{fraction of cake eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ They ate ${4}$ out of $5$ slices. They ate $\dfrac{4}{5}$ of the cake.